The present invention relates to monitors, and more particularly, to a flight crew response monitor for detecting an inattentive aircraft flight crew and raising their alertness level when required.
Long range flights involve hours of low crew activity during the cruise phase. With modern navigation and flight management systems, the crew role becomes one of monitoring progress and making position reports when crossing preestablished reporting points. The resulting boredom coupled with good equipment reliability can undermine the crew's attentiveness to flight status and progress. Furthermore, crew scheduling unavoidably exposes many crews to the adverse physiological effects of jet lag. Consequently, at least one pilot will often fall asleep during a long cruise segment, particularly when flying into the sun. In spite of his best effort to stay awake, it is suspected that a second pilot will occasionally doze off as well. This can result in a reporting point being missed or overshooting the point at which the descent should be initiated (top of descent) with the flight management system functioning normally. More importantly, a subtle equipment failure going undetected can result in wandering off course, departing the assigned altitude or upsetting airplane attitude to the point of requiring a dive recovery.
Although modern aircraft have crew alerting systems which provide prioritized alerts to the crew of detected failures, they do not detect all causes of departure from the planned flight profile. Even detected and annunciated failures may not be caught by an inattentive crew until the situation has substantially deteriorated. It has been recognized for some time that the solution lies in being able to measure the level of crew alertness and raise it when necessary.
Proposed solutions have ranged from a timer generated alarm to random questions on a display which require the pilot to respond, even though he may be busy doing something else. They have the shortcoming that they would very likely become an aggravation to an alert crewman. Nor do they alert the crew to a gradual departure from the programmed flight profile.
Prior art patent literature has included U.S. Pat. No. 3,312,508 to Keller et al., U.S. Pat. No. 3,922,665 to Curry et al. and U.S. Pat. No. 4,679,648 to Johansen which require a special physical response (pushing of button) from the operator to avoid an alert. In contrast, the present system normally requires no special response from an active crew to avoid an alert. In addition, these patents do not address the problem of drawing attention to subtle failures which an inattentive crew might not detect in a timely manner. Also the patent literature has included U.S. Pat. No. 3,925,751 to Bateman et al. and U.S. Pat. No. 3,947,809 to Bateman which relate to deviations from glideslope path not addressed by the present system.